Blockade Reduces Spasticity in Rat Spinal Cord Injury

Neurotransmitter receptor blockade may also reduce rigidity

THURSDAY, Oct. 25 (HealthDay News) -- Blocking certain neurotransmitter receptors may reduce spasticity and rigidity in a rat model of spinal cord injury, according to the results of a study published in the Oct. 17 issue of the Journal of Neuroscience.

Michael P. Hefferan, Ph.D., from the University of California San Diego, and colleagues blocked the AMPA receptor and the glutamate receptor 1 (GluR1) in a rat model of ischemic paraplegia to examine their effect on spasticity and rigidity.

The researchers found that an AMPA receptor antagonist suppressed peripheral muscle resistance, evoked electromyography activity, motor evoked potentials and the Hoffman reflex. GluR1 expression increased in the spinal cord and astrocytes of the spastic animals, and reducing the expression of GluR1 reduced spasticity and rigidity. An AMPA receptor antagonist could block the release of glutamate from astrocytes in culture after AMPA treatment.

"These data suggest that an AMPA/kainate receptor antagonist can represent a novel therapy in modulating spasticity/rigidity of spinal origin and that astrocytes may be a potential target for such treatment," Hefferan and colleagues conclude.

This study was partially funded by TorreyPines Therapeutics, and a study co-author is CEO of that company.

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